Energy generation and storage in portable packages has long been a subject of study and development. Storage of electrical energy in a compact form, such as in the form of a rechargeable battery and/or capacitor that can be readily charged and discharged, is of special importance. Rechargeable energy storage devices characterized by high power and high energy are necessary to power devices that have a wide range of electrical requirements. Examples of such devices include digital communication devices, power tools, and portable computers, to name but a few. In each of these devices, the instantaneous high power that can be provided by a capacitor is occasionally needed, while the high energy that can be provided by a battery is required at other times. Although most battery technologies offer enhanced energy capability, this is generally at the expense of maximum power.
One prior art solution has been to combine an electrochemical capacitor in parallel with a battery to meet the peak power requirements of pulsed power applications. This architecture can significantly enhance battery performance in terms of talk time, low-temperature performance, and/or cycle life. Unfortunately, such a solution requires incorporation of a separate component, i.e. the electrochemical capacitor, within the battery pack. This additional component adds to the volume and the complexity of the energy storage device, and thus is not the most desirable solution.
Accordingly, there exists a need to provide a novel electrochemical device that meets the needs of modern cordless pulsed power devices in a small package without the complexity associated with prior art solutions.